Extract bootstrap.dat to the data folder (all bootstraps are named bootstrap.dat, so be sure you’re using the correct one)

Launch the wallet, and wait for it to import the blocks (will take some time)

Do not attempt to access the wallet, or click the splash screen, as some wallets will crash

To monitor the progress, look in the coins’ data folder, and watch the blk0001.dat (or similar) increase in size. When it approaches the file size of the bootstrap.dat, you’ll know it’s almost complete

To create your own bootstrap.dat, from your own data files, or one of the blockchains available here, the easiest way is to use the command prompt, in Windows: